package io.renren.factory;

import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.MongoIterable;
import io.renren.config.MongoCondition;
import org.bson.Document;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Conditional;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * @author: gxz gongxuanzhang@foxmail.com
 **/

@Component
@Conditional(MongoCondition.class)
public class MongoDBCollectionFactory {

  private static final String TABLE_NAME_KEY = "tableName";
  private static final String LIMIT_KEY = "limit";
  private static final String OFFSET_KEY = "offset";

  private static MongoDatabase mongoDatabase;

  // 此处是为了兼容mongo相关内容和关系型数据库的静态耦合所导致的问题

  @Autowired
  private MongoDatabase database;

  @PostConstruct
  public void initMongoDatabase() {
    mongoDatabase = database;
  }

  /***
   * 通过表名获得查询对象
   * @author gxz
   * @date 2020/5/9
   * @param collectionName mongo的集合名(表名)
   * @return 连接查询对象
   **/
  public MongoCollection<Document> getCollection(String collectionName) {
    return mongoDatabase.getCollection(collectionName);
  }

  /***
   * 获得当前数据库的集合名称
   * 注: mongo相对关系型数据库较为特殊，查询表名无法分页，用stream实现
   * @author gxz
   * @date 2020/5/9
   * @param map 这是查询条件 和关系型数据库一致
   * @return 集合名称
   **/
  public static List<String> getCollectionNames(Map<String, Object> map) {
    int limit = Integer.valueOf(map.get(LIMIT_KEY).toString());
    int skip = Integer.valueOf(map.get(OFFSET_KEY).toString());
    List<String> names;
    if (map.containsKey(TABLE_NAME_KEY)) {
      names = getCollectionNames(map.get(TABLE_NAME_KEY).toString());
    } else {
      names = getCollectionNames();
    }
    return names.stream().skip(skip).limit(limit).collect(Collectors.toList());
  }

  /***
   * 获得集合名称总数(表的数量) 为了适配MyBatisPlus的分页插件 提供方法
   * @author gxz
   * @date 2020/5/9
   * @param map 这是查询条件 和关系型数据库一致
   * @return int
   **/
  public static int getCollectionTotal(Map<String, Object> map) {
    if (map.containsKey(TABLE_NAME_KEY)) {
      return getCollectionNames(map.get(TABLE_NAME_KEY).toString()).size();
    }
    return getCollectionNames().size();

  }


  private static List<String> getCollectionNames() {
    MongoIterable<String> names = mongoDatabase.listCollectionNames();
    List<String> result = new ArrayList<>();
    for (String name : names) {
      result.add(name);
    }
    return result;
  }

  private static List<String> getCollectionNames(String likeName) {
    return getCollectionNames()
            .stream()
            .filter((name) -> name.contains(likeName)).collect(Collectors.toList());
  }
}
